Multiphase coupled-buck converter - A novel high efficient 12 V voltage regulator module

The most popular VRM topology-multiphase buck converter operates at a very small duty cycle due to a high input voltage and a low output voltage. The performance of the multiphase buck converter suffers from the very small duty cycle. Alternative topologies with an extended duty cycle are explored in order to improve the efficiency without compromising the transient response. A novel topology named multiphase coupled-buck converter is proposed, which enables the use of a large duty cycle with recovered leakage energy and clamped MOSFET voltage. The input filter is further integrated in the proposed circuit to reduce the number of components. A 12 V-to-1.5 V/50 A VRM prototype demonstrates that the multiphase coupled buck converter can have a much better efficiency than the multiphase buck converter with the same transient response.